package com.itheima.reggie.filter;


import com.alibaba.fastjson.JSON;
import com.itheima.reggie.common.BaseContext;
import com.itheima.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 检查用户是否完成登录
 */
@WebFilter(filterName = "LoginCheckFilter",urlPatterns = "/*")  //拦截所有
@Slf4j
public class LoginCheckFilter implements Filter {
    //路径匹配器，支持通配符
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //向下强转
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        //A. 获取本次请求的URI
        String requestURI = request.getRequestURI(); //  /backend/index.html
        //System.out.println("uriiiiiiiii是："+ requestURI);
        //StringBuffer requestURL = request.getRequestURL(); //  http://localhost:8080/backend/index.html
        //System.out.println("urllllll是："+ requestURL);

        log.info("拦截到请求:{}" , request.getRequestURI());  //{} 占位符

        //定义不需要处理的请求路径
        String[] urls = new String[]{
                "/employee/login",     //登录按钮访问的路径
                "/employee/logout",    //退出按钮访问的路径
                "/backend/**",        //放行是因为访问主页有多个URI  例如：/backend/index.html不需要处理   /employee/page需要处理    /backend/favicon.ico不需要处理
                "/front/**",            //所以访问不成功
                "/common/**",
                "/user/sendMsg",
                "/user/login",
                "/doc.html",
                "/webjars/**",
                "/swagger-resources",
                "/v2/api-docs"
        };

        //B. 判断本次请求, 是否需要登录, 才可以访问
        boolean check = check(urls, requestURI);

        //C. 如果不需要，则直接放行
        if(check){
            log.info("本次请求{}不需要处理",requestURI);
            filterChain.doFilter(request,response);
            return;
        }

        //D-1. 判断登录状态，如果已登录，则直接放行
        if(request.getSession().getAttribute("employee") != null){
            log.info("用户已登录，用户id为：{}",request.getSession().getAttribute("employee"));

            //调用BaseContext来设置当前登录用户的id
            Long empId = (Long) request.getSession().getAttribute("employee");
            BaseContext.setCurrentId(empId);

            filterChain.doFilter(request,response);
            return;
        }

        //D-2、判断登录状态，如果已登录，则直接放行
        if(request.getSession().getAttribute("user") != null){
            log.info("用户已登录，用户id为：{}",request.getSession().getAttribute("user"));

            Long userId = (Long) request.getSession().getAttribute("user");
            BaseContext.setCurrentId(userId);

            filterChain.doFilter(request,response);
            return;
        }

        log.info("用户未登录");

        //E. 如果未登录则返回未登录结果，通过输出流方式向客户端页面响应数据
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
        //前端要求返回的是JSON形式   Controller类直接返回R.error("NOTLOGIN")是因为写了@RestController注解  页面发送AJAX请求 提交数据到服务端就是JSON形式
        return;  //终止函数执行
//        return R.error("NOTLOGIN");  写@Response注解也不行  因为该方法返回类型是void
    }


    /**
     * 路径匹配，检查本次请求是否需要放行
     * @param urls
     * @param requestURI
     */
    public boolean check(String[] urls, String requestURI) {
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url,requestURI);  //统配符有相似的东西都返回true  例如url：/front/**    URI：/backend/index.html
            if (match) {
                return true;
            }
        }
        return false;
    }
}
